Plug for core holes or the like



' Feb. 25, 1958' A. DERUMAUX $824,945

PLUG FOR CORE HOLES OR THE LIKE Filed Feb. 23. 1954 Inventor Attorney United States Patent PLUG FOR CORE HOLES OR THE LIKE Alfred E. Derumaux, Oshawa, Ontario, Canada, assignor to General Motors Corporation, Detroit, Mich., a corporation of Delaware Application February 23, 1954, Serial No. 411,682 3 Claims. (Cl. 219-38) My invention relates to a core or bore hole plug and in its most particular aspect concerns a combined lead-in and support plug for an electrical heating element adapted tobe confined in the water jacket of a cylinder block, especially the cylinder block of an automobile engine. Such elements are adapted to be energized from an ordinary 110 volt outlet and are desirable as assuring ready starting of the engine in cold weather.

Plugs heretofore proposed for the purpose indicated require tapping of the core hole formed in the cylinder block to receive the plug. This operation demands extra handling of the heavy blocks and is otherwise inconvenient. Moreover, it has been found that the screwedin plugs tend either to loosen in use or to become so fast in the block from corrosion as to make their removal, occasionally necessary to replace the heating element, extremely difficult, if not impossible. At best, some leakage through these plugs almost always occurs, the lost coolant tending to follow the course of the threads.

My invention has as its principal object to provide a plug which overcomes the aforementioned faults.

Other objects and features of the invention will be apparent from the following specific description of a preferred embodiment thereof. The description will proceed with reference to the accompanying drawings in which:

Figure 1 is a fragmentary section showing part of a cylinder block with the lead-in and support plug in place therein;

Figure 2 is a side elevation; and

Figure 3 is an exploded view of the several parts making up the plug.

In Figures 1 and 2, the cylinder block is denoted by the numeral 10, the particular wall shown being the external wall of a chamber 12 through which a coolant is circulated incident to the operation of the engine. A heating element 14, which may be of any appropriate type, is disposed within the chamber 12 in a manner assuring submergence thereof in the coolant.

The heating element is held by a plug body member 18 suitably bored to receive the bifurcated end of the element and the lead 20. Member 18 is threaded at 22 and terminates in a flange 24 backing an adapter ring 38 through a sealing gasket 37. Ring 38 has a rim portion 26 of relatively thin section forming a pocket 28 adapted to receive the tapered or wedge portion 29 of a sleeve member 30 surrounding the member 18. Such sleeve has a shoulder 32 which abuts the outer margin of the core hole when the assembly is secured in place.

A nut 34 carried by the member 18 operates to force the tapered portion 29 of the sleeve into the pocket 28. This results in expansion of the rim 26 against the annular wall 36 and provides an extremely tight fit assuring retention of the assembly and precluding loss of coolant.

Both the nut 34 and the left-hand end of the member 2,824,945 Patented Feb. 25, 1958 18 are of hexagonal conformation, this in view of the particular tools contemplated for use in the application of the plug. It is preferred to form the member 18, the sleeve 30 and the adapter ring of brass or similar metal.

Having thus described and illustrated my invention what I claim is:

1. In association with a coolant jacket surrounding a combustion engine, said jacket having an untapped hole therein, an assembly comprising: an electrical heating element disposed within the chamber formed by said jacket, said heating element being carried by a plug member extending through said hole, said plug member being formed to accommodate electrical leads connected to said element, adapter means at the inner end of said plug having a body portion and an expansible portion of relatively thin section, said body portion including a shoulder which with said expansible portion provides a pocket, and means received in said pocket to expand said expansible portion into engagement with the wall of said untapped hole.

2. In association with a coolant jacket, surrounding a combustion engine, said jacket having an untapped hole therein, an assembly comprising: an electrical heating element disposed within the chamber formed by said jacket, said heating element being carried by a plug member extending through said hole, said plug member having abutment means at its inner end, being formed to accommodate electrical leads connected to said element and including an unthreaded portion and a threaded portion, an adapter surrounding the unthreaded portion of said plug member having a body portion abutting said abutment means and an expansible portion of relatively thin section, said body portion including a shoulder which with said expansible portion provides a pocket, wedge means received in said pocket to expand said expansible portion into engagement with the wall of said untapped hole, and a nut on the threaded portion of said plug member externally of said chamber operating to load said wedge means.

3. In association with a coolant jacket surrounding a combustion engine, said jacket having an untapped hole therein, an assembly comprising: an electrical heating element disposed Within the chamber formed by said jacket, said heating element being carried by a plug member extending through said hole, said plug member having a flange at its inner end of a diameter less than that of said hole, being formed to accommodate electrical leads connected to said element and including an unthreaded portion and a threaded portion, an annular adapter surrounding the unthreaded portion of said plug member having a body portion abutting said flange and a rim portion of relatively thin section, said body portion including a shoulder which with said rim portion provides a pocket, and an annular wedge member received in said pocket to expand said rim portion into engagement with the wall of said untapped hole, said wedge member carrying a flange abutting the coolant jacket externally of said chamber and being loaded by a nut on the threaded portion of said plug member.

References Cited in the file of this patent UNITED STATES PATENTS 351,414 Warner Oct. 26, 1886 410,848 McHugh Sept. 10, 1889 848,493 Redenbaugh Mar. 26, 1907 1,103,171 Bower July 14, 1914 2,401,847 Urbant et a1 June 11, 1946 

